"Considering the failures of the war on drugs, perhaps our modern societies should look into the past and learn something from 'the primitive' so that we might find out how to maximize the potential benefits and minimize the potential for harm of substances that humans have been using for millennia," Guerra-Doce said in the email.

http://www.huffingtonpost.com/2015/02/12/prehistoric-drug-use-thousands-of-years_n_6622446.html